MCFCs are under development for natural gas and coal-based power plants. MCFCs operate at temperatures in excess of 600 deg. C., using an electrolyte comprising molten carbonate salts in a permeable, chemically inert ceramic matrix, such as beta-alumina. They are more efficient at power conversion than some other fuel cells—with capture and use of waste heat, overall fuel efficiencies of MCFCs can reach 85 percent. A further advantage is that because of their high operating temperatures, they can reform fuels such as natural gas to hydrogen internally, thereby potentially eliminating the need for an external reformer. Moreover, MCFCs are resistant to poisoning by carbon monoxide or carbon dioxide, so facilitating their integration with fossil fuel power plants. In particular, MCFCs can be used to                increase the efficiency of fossil fuel power plants by reacting exhaust gases to generate electricity, and        reduce environmental impact by separating out carbon dioxide from the exhaust gases.        
For example, U.S. Pat. No. 7,396,603 B2 discloses a fossil fuel power plant arranged in tandem with a MCFC, in which flue gases containing about 10% CO2 together with 19% water and 9% oxygen are fed directly to the cathode side of the MCFC. At the same time, fuel such as natural gas is input to the anode side, where it is reformed to liberate hydrogen. Electrochemical reactions in the MCFC effectively result in a major proportion of the CO2 in the flue gas being transferred from the cathode side to the anode side. The CO2-enriched gas is then exhausted from the anode side for subsequent processing, including separation and sequestration of the CO2.
Published European patent application EP 0 418 864 A2 discloses a broadly similar method and apparatus.
The present patent specification discloses a fossil fuel power plant having improved integration with an MCFC arrangement for CO2 separation, and a method of operating the power plant.